Gyroscopic position finder



GYROSCOPIC POSIT original Fi1e Nv. .7, 1931 F. M YOUNG 10N FINDER s'sheeis-sheet 1.

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ATTORNEYS. j

July 7,1936- F. M. YOUNG 2,046,890

GYROSCOPIG POSITION FINDEF- Original Filed Nov` 7, 1931 8 Sheets-Sheet 2 v INI/ENTOR. u F//c/zer '/W ,Veur/g .uy' 7? M36., F. M. YouN 4GYROSCOPIC POSITION FINDER Orgirxal Fliled Nov. '7, 1931 8 'Sheets-Sheet 4 ATTORNEYS.

July 7, 1936, M, YOUNG 2,046,890

GYROSCOPIC POSITION FINDER Orgal Filed-Novf, 1951 8 Sheets-Sheet 5 L j@ 67 *566 f5.2

v L Q PIE- 7 544 o 546 545 He/c/yZ/{ZZE/Ngng.. /ykwwwf ATT *542 l ORNEYS July 7, 1936. FQM. YOUNG 2,046,890

' n GYROSCOPIG POSITION FINDER Original Fild Nov. '7, 193i 8 Sheets-Sheet 6 FIE.

ATTORNEYS.

July 7, 1936. F .9., YOUNG 2,046,890

' GYROSOPIC POSITION FINDER originl Filed Nov; '7, 1931 8 sheets-sheet 7 Hlang/lluz/a b 3 Z 5?/ ATTORNEYS.

`July `7, 1936. F M YOUG 2,046,890

GYROSCOPIC POSITION FINDER [ai/ade yro.

i F111 M mem.: Jui, 7, 193s l UNITED STATES PATENT OFFICE aussen Gmoscorrc rosrrIoN mima Fletcher M. Young, Berkeley, Calif., assignor of one-half to Michael C. Casserly, San Mateo,

Calif.

Original application November 7, 1931,- Serial No.

Divided and this application September 27, 1932, Serial No. 635,065

9 Claims.

,l scopic means for indicating longitude and latitude, but such proposals were based on the erroneous presumption that a gyroscope, when once set in motion, will 'necessarily maintainits spinning axis ilxed in space.

l While it is true that the'spinning axis'tends to remain ilxed in spacel this condition persists only so long as there is no external force acting -on the gyroscope. Any gyroscope within the `mnuence of the earths gravitation will be rotated with the earth, and the force of this rotation will have its effect on the direction of -the spinning axis of the gyroscope and will cause the axis to i precess under the influence of theA applied force. Also, some frictional forces are necessarily present in any gyroscope system, and these forces will likewise disturb the direction of the spinning axis unless counteracted or compensated for. When the gyroscope is mounted on a moving body, such as a ship, numerous forces arising from the pitching and rolling of the ship, its change in course and its change in speed, all have their eilect on the spinning axis oi' the gyroscope. Even the force 'resulting from the movement of the earth in its orbit may in time be felt by the gyroscope. Prior 4 35 gyroscopic position ilnders have failed to counteract, to neutralize, or to eliminate any of these forces, and Ior this reason have been entirely inoperative to produce the results sought. The mere fact that the tedious methods o! dead reckoning and of resorting to astronomical observ vations are still universally employed in ilnding positions, is conclusive that no automatic position finder has heretofore been devised which is accurate withinl practicable limits.

It is an object of my invention to provide an automatic gyroscopic position ilnder which is accura-te and dependable, and which will ailord a direct position indication which need not be translated by computation. f

Another object is to provide means in a device `mi! t'he characterdescribed for counteracting the eiiect of external forces.

Another object is to provide a gyroscopic position ilnder in which novel means is provided for minimizing .and counteracting the eiIect of frictional forces.

Still another object is to provide a gyroscopic position iinder in which a horizon instrument is employed for providing a basic plane from which 5 the coordinates of the position can be derived.

Still another object is to provide a longitude indicating gyroscope in which possible errors due to external forces are eliminated, neutralized or counteracted. e i Another object is to provide a longitude indieating gyroscope in which the 'effect oi' the force oi' the earths rotation is automatically neutralized.

'Ihese and other objects and advantages are ob- 15 tained in the embodiment of my invention illustrated in the accompanying drawings, in which:

Figure 1 is a diagrammatic view illustrating the principles of operation of the longitude indicating apparatus.

Figure 2 is a plan view partly in section, of an` apparatus incorporating the present invention. taken on line 2-2 of Fig. 3.

Figure 3 is a cross sectionalview taken along the planes indicated by line 3-3 of Figure 2. 25

Figure 4 is a cross sectional view taken along the plane indicated by line 4 4 of Figure 3.v

Figure 5 is a detail view, partly in section, showing the apparatus for rotating the gyroscope in retrograde about an airis parallel to the polar axis 30 of the earth.

Figure 6 is `a.det`ail view of'the'control contacts for controlling the energizatlon of a follow up motorand one of the retrograde motors s'hown in Figure 5. 35

Figure 7 is a circuit diagram.

Figures 8 to 10 are detail views of the longitude indicator repeater card.

Figure 11 is a detail view of a dial and an impulse transmitter actuated in accordance with 40 the movements of the'gyroscope, taken on line lI-II oi Fig'. 3.

Figure 12 is a circuit'diagram.

Figures 13 to 15 illustrate` diagrammatically the general relationship of the component parts 45 of the position ilnder'.

The invention claimed herein relates particularly'to mechanism incorporated in a complete position nder installation for indicating -a position in terms of longitude. In this connection the 50 present case ls a division of my copending application Serial No. 573,641, filed November '1, 1931. and entitled Gyroscopic position nder.

The complete position ,finder with whicl` I prefer to employ my invention comprises a pair 55 of gyroscopes, one of which is employed for indicating longitude and the other for indicating latitude. Preferably, both of these gyroscopes are free and non-pendulous for minimizing friction and for counteracting any tendency of the spinning axes of the gyroscopes to change their respective directions in space under the inuence of external forces.

The two gyroscopes referred to above are preferably utilized in conjunction with a third gyroscope which is made north-seeking and pendulous, so that its spinning axis continually takes a horizontal position or one tangent to the earths surface and lying in the north and south plane. Gyroscopes of the last mentioned type are in common usage as compasses on ships and, if desired, the gyrocompass which is Vusually utilized on ships can serve as the third gyroscope. A suitable hori- ,Y

zon instrument is also utilized to establish a horizon line or a plumb line from which the coordinates can be determined. As will be presently explained, such a horizon instrument can be connected to certain other partsof the apparatus by suitable means.

The directive force of the earths rotation. which is employed to direct the spinning axis of the latitude gyroscope disclosed in said copending application, is counteracted in the longitude gyroscope by rotating the longitude gyroscope about an axis parallel to the earth's polar axis and at the same rate as the earth's rotation, but in the opposite direction. Thus, the precession which would otherwise be caused by the force of the earths rotation, is neutralized by the force set up by the retrograde rotation given to the gyroscope, and the gyroscope remains in equilibrium between these two forces. So long as these forces remain exactly equal, therefore, there will be no tendency of the gyroscope axle to change its direction in space. If the gyroscope is mounted on a ship, and the ship moves in a direction which has an easterly or westerly component, the resultant rotation of the gyroscope due to the rotation of the earth and the movement of the ship over the surface of the earth is greater or less than one revolution in twenty-four hours, by an -amount which is determined by the speed and the course of the ship. In order to maintain the gyroscope in. equilibrium under these conditions the retrograde rotation imparted to the gyroscope must be increased or diminished accordingly, so that the retrograde rotation neutralizes exactly the resultant rotation of the gyroscope due to the earth's rotation and the movement of the ship.

North and south movements of the ship will not aifect the rate of rotation of the gyroscope about the axis of the earth and need not be taken into consideration.

The principles on which the longitude gyroscope operates are illustrated in Fig. 1. The gyroscope is preferably set in motion with its spinning axis lying in a plane parallel with the plane of the equator and with its disc parallelto the plane of a known meridian atl a denite time, chosen as the origin, preferably the meridian at Greenwich at noon. As the earth rotates about its axis, the gyroscope is given a retrograde rotation about an axis parallel with the axis of rotation of the earth and at the samerate, but in the opposite direction. The retrograde rotation of the gyroscope is increased or diminished in accordance with the speed and direction of the ships travel over the earth 4to maintain the disc of the gyroscope parallel with thev noon position in space of the meridian at Greenwich. Thus.

the gyroscope remains relatively fixed in space. The longitude, of any position is determined by laying oi the hour angle of Greenwich eastwardly from the zenith line of the gyroscope disc, thereby obtaining a line parallel to the plane of 5 the meridian at Greenwich at that time. The longitude of the place is then given by the angle between the line thus obtained and the vertical plane through the meridian at the location of the instrument.

Referring now to the examples illustrated in Fig. l, K illustrates the position of the gyroscope disc when the gyroscope is at 60 west longitude at noon Greenwich, the latitude being It will be noted that the axis of the gyroscope lies in a l plane parallel with the plane of the equator and that the disc of the gyroscope is in a plane parallel with the noon position of the Greenwich meridian. The hour angle of Greenwich is zero, so no angle is laid oi from the zenith line of the gyroscope disc, the gyroscope disc itself giving the parallel of the meridian at Greenwich at that time. Measuring the angle between the zenith line of the gyroscope disc and the earths vertical, we obtain 60, the longitude of the place.

Assuming now that the'ship is traveling westward at the rate of one-half degree per hour, the position of the gyroscope K will be moved by the earth's rotation and by the motion of the ship to K at 2:00 p. m. Greenwich time. During this 30 motion in Space of the gyroscope, it has been given a retrograde rotation equal to the resultant rotation about the earth's axis, so that its axle remains parallel to the plane of the equator and its disc remains parallel with the noon position in spacev of the Greenwich meridian. The hour angle r of Greenwich is 2/24ths 'of 360, o r 30, and this angle is laid off in an eastward direction from the origin mark of the gyroscope case giving the line n which is parallel to the meridian at Greenwich at 2:00 p. m. The angle between the line n and the earths vertical or plumb line is equal to 60 plus the ships angular movement about the axis of the earth or 6l", indicating 61 west longitude. If the ship had been traveling eastward instead of westward, its angular movement would have been negative instead of positive and the angle between the line n and the plumb line in that case would have been 59, and the longitude indication would have been 59 west longitude.

The position of the gyroscope at east longitude at 2:00 p. m. is shown atK". The hour angle r of Greenwich is laid 01T as before from the origin mark of the gyroscope case, giving the line n' parallel to the meridian at Greenwich at that time. The angle between the line n' and the plumb line under these conditions measures 30, indicating 30 east longitude.

In general, therefore, the method of indicating the longitude comprises rotating the gyrocope to counteract-the effep't of the earth's rotation.'- laying oiI the hour angle of the meridian chosen as the origin in the direction of the earth's rotation to obtain a line parallel with the plane of the origin meridian at the time of observation, and then measuring the angle between the last men ticned line and the line in the vertical plane through the instantaneous meridian parallel to the plane of the equator.

Referring now toFigs. 2 to 15, I have shown a gyroscope 30| supported for rotation in a plurality of gimbal rings and maintained with its axis of rotation in the plane-of the equator and with its and normal to the Equator.

ldisc parallel to a chosen meridian plane at a definite time. The origin meridian is' preferably the meridian at Greenwich and the disc of the gyroscope lies in a plane parallel to the plane of this meridian at noon Greenwich. As the earth rotates and as the ship moves in longitude over the surface of the earth, the gyroscope is turned accordingly to maintain its disc parallel with the noon position of the Greenwich meridian.-

For supporting the gyroscope a binnacle 302 is provided which is mounted in any suitable manner on the ship. A floating ring 303 is suspended in springs 304 from the binnacle 302. A ring 306 is carried in fore and aft trunnions 301 and 308 in ring 303. A leveling motor 303 is provided for leveling the ring 306 athwartship and is controlled by a suitable horizon instrument. A ring 3|| is carried in athwartship trunnions in ring 306 and is kept in a vertical plane by motor 3|2 (Fig. 4), similar in operation to the motor described in connection with the latitude instrument of the aforesaid co-pending application. Carried in vertical trunnions 3|3l and 3|4 in ring 3|| is a ring 3|6 and a motor 3|1 (Fig. 3), operating in amanner similar to the motor 1| of the aforesaid latitude instrument, is provided for maintaining the ring 3|6 in a plane parallel to the E-W vertical plane. Carried in east and west trunnions in ring 3|6 is a ring 3|3. Ring 3|3 is kept in a plane parallel with the plane of the Equator by a motor 3|9 mounted on ring 3|6 and carrying a pinion 32| -which meshes with a gear 322 on ring 3| 6. The

motor 3|9 receives impulses from a latitude repeater transmitter to maintain the ring 3|6 parall'el with the plane of the Equator.

Rigidly secured to ring 3|3 and extending at right angles thereto to lie in the north and south vertical plane is a rin'g 323. ring 324 which is mounted for rotation about trunnions 326 and 321j'which are in a N-S plane Ring 324 carries the gyroscope housing 30| in trunnions 320 and 323 lying parallel to the plane of the Equator. Interposed between the gyroscope housing 30| a d the ring 324 is a follow-up ring 33| which is caused to follow the movements of the gyroscope about trunnions 328 and 323.

For causing the ring 33| to follow the movements of the gyroscope, a motor 332 is provided which is mounted on ring 324 and which carries a pinion 333 meshing with a gear 334 rigidly secured to the ring 33|. An arm 336 mounted on trunnion 326 to rotate therewith carries sets of contact wheels 331 and 333 (see Fig. 6) which cooperate with follow-up contacts 333 and 34| carried by ring 33| to energize the motor 332 to bring the ring 33| back into the plane of the gyroscope disc.

whenever there has been relative rotation between the ring 33| and the gyroscope disc to disturb this relationship.

For rotating the gyroscope housingabout the trunnions 326 and 321 in a direction opposite to the direction of the earth?s rotation and at the same rate, I provide a motor 342 which is mounted on ring 323; Motor 342 carries a pinion 343 which meshes with a gear 344 secured to a shaft 346 which carries a worm 341. Worm 341 drives a worm gear 346 at the rate of one revolution in 24 hours and in a direction opposite to the direction of rotation of the earth. For transmitting the rotation o'f gear'343 to thegyroscope housing 30|. gear 343 is fixed to a sleeve 343 which carries a Aworm gear 35| similar in every respect with the gear 343. Sleeve 343 is rotatable relative to the trunnion 326 and relative to\the Ring 323 carries al For accomplishing this object,

ring 323. A reduction gear train comprising the worm 352. gear 353 and pinion 354 connects the gear 35| with a motor 356 mounted on ring 324. Motor 342 and motor 356 are similar to each other, but motor 342 is energized continuously to rotate 5 at a constant speed in one direction while motor 356 is normally de-energized and is adapted to be energized to rotate in one direction or the other to modify the edect of rotation o f motor 342. Assuming that the motor 356 isde-energized, the motion of gear 340 which rotates at a constant rate of one revolution in twenty-four hours is communicated to the ring 324, the gear train 352 to 354 acting under such condition as a rigid connection between gear 35| and the ring 324. Ring 324, therefore, rotates at the rate of one revolution in twenty-four hours in a direction opposite to the direction of rotation of the earth and carries with it the gyroscope housing 30|. During this rotation of the gyroscope, the 20 spinning axle remains east-west.

Motor 356 is energized only when the ship is traveling in a course which has an easterly or y westerly component and the duration of the energization and the direction of` rotation of the 25 motor 356 is such that the rotation of the gyroscope is modified in accordance with the motion of 'the ship over the surface of the earth. In other Words, when theship is traveling west, the resultant rate of rotation of the entire device about the axis of the earth is less than one revolution in twenty-four hours, and the motor 356 is energized to turn the ring Y324 in the same direction as the earths rotation' by an vamount which is suillcient to eliminate the effect of the ship's movement toward the west.' In a like manner, if the ship is traveling eastward, the motor 356 is energized to speed up the rotation of the gyroscope in accordance with the motion of the ship about the axis of the earth. Ink effect, the plane of the gyroscope remains fixed relative to absolute space while thev gimbal 'rings are rotated relative to the gyroscope about the trunnions 326 and 321, to enable the gyroscope to maintain such xed relation. When the ship is stationary or when it moves due north or due south, the rate of rotation is exactly equal to the rate of the earths rotation about its axis, but in the-opposite direction. When the shipmoves east or. west, however, and thus increases or dev5C creases the virtual rate of rotation of the instrument about the axis of the earth. the retrograde rotation of the gyroscope is modined to neutralize the errent of the virtual rotation; i

automatic 55 means is provided for energizing the motor 356 to modify the effect of motor 342. As long as the gyroscope is rotated at a rate which causes its plane to remain parallel with its original direction in space. the directive force of the earths 60 rotation willnot be felt by the gyroscope. If, however, the ship moves to the east or to the west. the rate ofthe rotation of the gyroscope about trunnions 326 and 321 must be increased or de-- creased accordingly, otherwise the plane of the .65 gyroscope disc will deviate from its original position in space and the directive force of the earths rotation/will be felt. As soon as the directive force is felt by the gyroscope. its axle will begin to precess, the amount, and direction of preces- 7 0 sion being in accordance with the directive force arising from the ships rotation about the axis f of the earth. This precession will cause the gyroscope to turn about the trunnions 323' and 325 v relative to the ring 324. In order to overcome this precession, the gyroscope rotation about trulinions 326 and 321 must be modied by an amount sufcient to set up an equal and opposite precession. The amount of supplemental rotation about trunnions 326 and 321 and its direction are such that the gyroscope will be brought back into a plane parallel with its original plane when the precession is neutralized.

For energizing motor 356 a contact arm 36| is secured to rotate with trunnion 328. Contact arma 36| carries contact wheels 362 and 363 `which cooperate with contacts 364 and 366 carried byV ring 324. When the gyroscope precesses it turns in one direction or the other relative to the ring 324, thus indicating that the rate of rotation of the gyroscope has at that instant varied from the virtual rate of rotation of the ship about the axis of the earth. Contacts 364 and 365 cooperating with the contact arm 36| thereupon complete a circuit to motor 356 to cause it to move the gyroscope back into the plane of origin. In doing so, the rate of rotation of the gyroscope is modified to equal the combined eect of the ships motion and the earths motion relative to the axis of the earth. The plane of the gyroscope disc is in this manner kept in a. plane parallel with the plane in space of the meridian which was chosen as the origin.

The circuit diagram for operating the motors 332, 342 and 356 is shown in Fig. 7. Motor 342 is connected directly to a source of regulated current impulses to rotate the gyroscope housing in retrograde at the rate of one revolution in twenty-four hours. If the gyroscope shows precession relative to the ring 324, certain ones of the contacts 364 and 366 are bridged, the upper contacts 364 closing simultaneously with the lower contacts 366 and the lower contacts 364 closing simultaneously with the upper contacts 366.

Assuming the direction of precession is such that upper contacts 364 and lower contacts 366 are bridged, current will flow from one side of the source of current, through conductor 31|, upper contacts 364, motor 356, conductor 312, lower contacts 366, through conductor 313 back to the other side of the source of current. The m'ptor 356 will then modify the rotation imparted to the gyroscope by motor 342 to bring the plane of the gyroscope back into the plane of ring 324. If the direction of precession is in the opposite direction, lower contacts 364 and upper contacts 366 are closed, thereby energizing the motor 356 in the opposite direction to modify the rotation of the gyroscope housing so that the gyroscope disc is again brought into a plane paralleljwith its original position. Precession of the gyroscope also causes the contacts 339 and 34| to be closed to energize the motor 332 in the proper direction to cause ring 33| to followthe precession of the gyroscope. While it is not desired to permit the gyroscope to precess out of the plane of is origin and to remain out of that plane, such precession, when it occurs. is employed to indicate when the gyroscope has moved out of its original plane and thus aiords an indication when the retrograde rotation of the gyroscope is not exactly equal to the virtual rate of rotation of the ship about the earths axis.

Thus, in my longitude apparatus, the directive force. o! the earths rotation is employed to indicate the relationship of the plane of the gyroscope disc at any ,instant relativeto the original plane. If the plane of the gyroscope disc is parallel to the original plane, no precession will be 'caused-by the directive force of the earth's rotation, because the parallel relationship of the gyroscope disc indicates in itself that the directive force of the earths rotation has been exactly neutralized by the directive force set up by the retrograde rotation of the gyroscope. If, on the other hand, the directive force of the earth's rotation is felt, it indicates that the retrograde rotation of the gyroscope is either too fast or too slow, on account of the movement of the ship in aneasterly or westerly drection. The rate of 4retrograde rotation must then be increased or de` creased in accordance with the movement of the ship in longitude in order to neutralize the directive force of the earth's rotation compounded with the travel of the ship. The amount by.

which the retrograde rotation of the gyroscope differs from; the rate of the earths rotation is, therefore, the measure of the ships movement in longitude. An indication of the longitude can be obtained, therefore, by subtracting the rotation of the earth from the total retrograde move- `ment of the gyroscope, thereby obtaining the movement in longitude from the original position of the gyroscope, and adding to the result the longitude in which the gyroscope was started.

For accomplishing this calculation automatically, an indicator card, such as that shown in Figs. 8, 9 and 10, can be employed. A relatively stationary housing 316 is provided and a motor 311 Isecured to the housing carries a. pinion 318 which meshes with a gear 319. The rate of rctation of the motor 311 is such that the gear 319 rotates at a rate which is equal to the retrograde rotation of the gyroscope. The gear 319 is secured to a shaft 38| which rigidly carries a disc 382. Disc 382, therefore, is also rotated at a rate which equals -the rate of the retrograde rotation of the gyroscope, preferably in the direction of the arrow shown on the disc. The rate of retrograde rotation of the gyroscope is exactly 360 in twenty-four hours when the ship is stationary. but varies from this rate when the ship moves in longitude. Mounted on gear 819 is a motor 363 which carries. a pinion 386 meshing with a gear 386. Gear 386 is secured to a hub 361 which is mounted for rotation relative to the shaft 63|. Also secured to hub 381 ls a ring 366 which surrounds the disc 362. Ring 388 is adapted to rotate in the direction of the arrow marked thereon relative to the disc 382 at a rate of exactly 360 in twenty-four hours. Since the disc 382 moves counter-clockwise relative to the housing 316 at the same rate that the ring 386 moves clockwise relative to the disc 382, when the ship is stationary, the ring 383 will remain stationary relative to the housing 316 under this condition. When the ship moves in longitude, however, the rate of rotation of disc 382 is increased or decreased accordingly and the amount by which this rate differs from the rate of rotation of ring 388, will be indicated by the relative movement of 388 with respect to the housing 316. The ring 388 is graduated about its outer periphery from zero to 180 in each direction, as at 389. and these graduations cooperate with a zero mark 39| and a Vernier scale 392 on the housing to indicate the angular relationship of ring 38| with respect to the housing. A second zero mark 334 cooperates with the graduations 369 to indicate the supplement of the angle indicated at the zero mark 38|. Thezero mark 39| is used in making `west longitude readings and the zero mark 383 is used in making east longitude readings..

The inner periphery of ring 386 is graduated from zero -to 360, as at 394, and a zero mark 336 place in which thel apparatus is started. 'Iheretrunnion 321.

after. the disc 382 will rotate counter-clockwise at the rate of 360 in twenty-four hours, relative to the zero marl: on the scale334, thereby measuring the time at Greenwich in terms of angular displacement. As long as the ship does not move -in longitude, the ring 388 will move clockwise relative to the disc 382 at the same rate that the disc 382 moves counterclockwiserelative to the housing 316, the ring 388, therefore, remaining stationary relative to the housing 316 and constantly indicating the unvarying longitude.

Now, if the ship moves east or west and therefore in longitude, the retrograde rotation of the gyroscope must be modined accordingly to maintain the gyroscope disc parallel to the plane of its original position. 'I'he ring 388 will be moved under this condition relative to the housing 316 andthe new longitude to which the ship has moved will be indicated by the scale 383.

'I'he position of the dials in Fig. 8 indicates that the ship is at 30 west longiture at 6:00 p. m.

Greenwich time. The zero mark 398 represents the position of the meridian at Greenwich at noon, and the angular displacement of the zero mark 336 from the zero point on the scale 394 is equal to the Aangular displacement oi' the meridian at Greenwich at 6:00 p.' m. relative to its noon position. Comparing the readings shown in Fig. 8 with the notationsemployed-in Fig. 1 for the position K', the zero mark 386 represents the zenith line of the gyroscope disc, the zero mark on the scales 389 and 364 represent the line n, and the zero mark 38| represents the vertical or plumb line of the earth. y

For transmitting the retrograde rotation of the gyroscope to the disc 382, I have shown a gear 40| (Figs. 3 and 11) secured to the ring 324 to rotate therewith relative to the ring 323 about the Meshing with the gear 40| is a pinion,402 and securedA to the shaft 403 fof the pinion are a pair of contact arms 404 and 406. Contact arms 404 and 406 sweep over a plurality of segments 401 (Fig. 1l), thereby setting up a sequence. of electrical impulses which are transmitted to the motor 311. Motor 311 is therefore energized in accordance with the angular displacement between rings 323 and 324, which is the measure of the retrograde rotation of the gyroscope. The gear ratio of the train between motor 311 and disc 382 is such thatthe disc 382 rotates relative tothe housing 318 at exactly `the same rate as the gyroscope is rotated retrograde.

For energizing motor 383 a similar 'repeater circuitv is provided, but slip ring connections are 'employed since the motor 383 is carried by the" gear 316 and thus rotates relative to the housing 316. The impulses for energiring motor 383 are obtained from the transmitter actuated by the ship's chronometer or any other accuratetiinev measuring device in ,such a manner that the fre'qency of the impulses is exactly 'Sumcienl'li rotate the ring 388 relative to the disc 382 at the rate of 360 in twenty-four hours. Thus, I have shown a transmitter having contact arms 484' and 406 carried by a shaft 403' which is rotated by a clock to set up a sequence of accurately regulated electrical impulses as the arms 484' and 406' sweep over the segments 401'. The impulses thus obtained are transmitted to a set of four slip rings 408 (Fig. 9), mounted onthe housing 316 and insulated electrically from one another.

'A set of four contact wheels 403 each making electrical contact with one of the rings 408 complete the path for the electrical impulses through conductors 4|0 connected to the ileld windings of motor 383. In this manner the motor 383 is energized'to rotate the disc 382 relative to the ring 388 at a rate of exactly 15 per hour at all times.

Preferably, an indicating arm 4II (Fig. 11) is secured to the-ring323 whichcooperates with a graduated scale'4l2 on or carried by the gear`40| to indicate the angular displacement of the gyroscope from a i'lxed direction. This scale can be employed for initially placing the disc of the'syroscope in the desired starting position.

In explanation of the interelation of my latitude and longitude gyroscopes it may be further explained that the retrograde rotation of the' longitude gyroscope is for the Purpose of eliminating the effect of the earths daily rotation upon the gyroscope. 'I'he retrograde rotation must therefore be in a plane parallel to the plane of the earths rotation, that is, the plane oi' the equator which is the same thing. The axis f the retrograde rotation must be at all times parallel to the earths polar axis. To fulfill this requirement the north and south axis of the longitude gyroscope, about which the retrograde motor turns the instrument, is kept elevated to the angle of the latitude by repeater controls from the latitude instrument, or in other words the north and south axis of the longitude instrument is kept parallel to the axle of the latitude gyroscope, except when the direction of that axle requires correction due 'angle between the axle and the earths north and south horizontal being equal to the latitude of the place. It is thus seen that the latitude instrument will function properly without aid or control from the longitude instrument, but that the longitule instrument is dependent upon the latitude instrument for proper functioning, .since if the requirement stated in the preceding paragraph is not fulillled, the longitude instrument will not indicate the correct angles of longitude.

The only means at hand for so controlling the ditrument lies in the use of the latitude instrution of the north-south axis of the longitude The general layout of the component parts 'of a complete installation incorporating my invention is illustrated in Figs. 13l to 15.

sired number of repeater instruments i3 can the gyroscopic instruments can be placed in the position whicfhis most satisfactory for their opbe placed at convenient points on the ship, while f The compass which is employed in my position nder may be the ships gyrocompass or may be a gyrocompass designed especially for use with my invention.

It is to be understood that certain expedients now in common practice for improving the operation of gyrocompass installations can be incorporated in my gyroscopic position nder, wherever such expedients are applicable.

While I have shown and described a preferred embodiment of my invention, it is to be understood that I do not wish to be limited thereto, since the invention as defined in the appended claims can be embodied in other forms.

I claim:

l. In a gyroscopic device for indicating geographic positions, a gyroscope adapted to be set in operation with its spin axis parallel to the plane of the equator, and means for insuring stable retrograde rotation of said gyroscope about an axis parallel to the polar axis of the earth in Y a direction opposite to the direction of the earths rotation and at a rate which is suicient to maintain the disc of the gyroscope parallel to the plane of its original position, said means including motive means responsive to precessional movements of the gyroscope about an axis normal to the two above-mentioned axes.

2. In a gyroscopic device for indicating geographic positions in terms of longitude, a gyroscope having its disc parallel to the noon position of the meridian of Greenwich, and adapted to be set into operation with its spin axis parallel to the plane of the equator, means for effecting retrograde rotation of said gyroscope about an axis parallel to the polar axis of the earth in a direction opposite to the direction of the earths rotation and at a rate which is suicient to maintain the disc of the gyroscope parallel to the plane of the noon position of the meridian of Greenwich, means for automatically laying off the hour angle of the meridian of Greenwich from the zenith line of the gyroscope disc, and' means for automatically indicating the angle between the line thus obtained and the earths plumb line through the gyroscope.

3. In a gyroscopic device for indicating geographic positions, a gyroscope adapted to be set in operation with its spin axis parallel to the equator, a supporting structure for said gyroscope, means interposed between said supporting structure and said gyroscope serving to carry the gyroscope for three degrees of freedom relative to the support, said last means including a gimbal ring capable of having three degrees of freedom with respect to the supporting structure and with respect to which the gyroscope may have like freedom of movement, said ring being adapted to be maintained in a predetermined angular positioning with respect-to the plane of the equator and the earths north and south axis, and continuously operating driving means interposed betweenv said gimbal ring and the gyroscope.

4. In a gyroscopic device for indicating geographic positions, a support adapted to be carried by a ship or like moving structure, a gyroscope carried by the support and adapted to be set into operation with its spin axis parallel to the equator, meansvserving to interconnect the support with the gyroscope whereby the gyroscope is carried for three degrees of freedom, said last means including a gimbal ring capable of having three degrees of freedom with respect to the support and with respect to which ring the gyroscope is also capable of having like movement, means for maintaining a gimbal axis of said ring parallel to the earths north and south axis, said gimbal ring being also restrained against rotation about said axis, and driving means interposed between said gimbal ring and the gyroscope and serving to insure relative rotation about said gimbal axis between said gimbal ring and the gyroscope at a rate suiiicient to maintain the gyroscope in stable equilibrium with its spin axis parallel to the equator and irrespective of orientation of the device in any direction.

' 5. In a gyroscopic device for indicating geographic positions, a support adapted to be carried by a ship or likemoving structure, a gyroscope adapted to be set into operation with its spin axis parallel to the equator, means serving to interconnect the support with the gyroscope whereby the gyroscope is carried for three degrees of freedom, said last means including a gimbal ring capable of having three degrees of freedom with respect to the support and with respect to which ring the gyroscope is also capable of having like movement, means for maintaining a gimbal axis of said ring parallel to the earths north and south axis, said gimbal ring being also restrained against rotation about said axis, and driving means interposed between said gimbal ring and the gyroscope and serving to insure relative rotation about said gimbal axis between said gimbal ring and the gyroscope at a rate sufficient to maintain the gyroscope in stable equilibrium with its spin axis parallel to the equator and irrespective oforientation of the device in any direction, said driving means including a motor adapted to eiect a rate of relative rotation between said ring and said gyroscope equal to the rate of rotation of the earth and another motor serving to effectively increase or decrease said rate of drive in response to orientation of said device in easterly or Westerly directions.

6. In a gyroscopic device for indicating geographic positions, a support adapted to be carried by a ship or like moving structure, a gyroscope adapted to be set into operation with its spin axis parallel to the equator, means serving to interconnect the support with the gyroscope whereby the gyroscope is carried for three degrees of freedom, said last means including a gimbal ring capable of having three degrees of freedom with respect to the support and with respect to which ring the gyroscope is also capable of having like movement, means for maintaining a gimbal axis of said ring parallel to the earths north and south axis, said gimbal ring being also restrained against rotation about said axis, and driving means interposed between said gimbal ring and the gyroscope and serving to insure relative rotation about said gimbal axis between said gimbal ring and the gyroscope at a rate sumcient to maintain the gyroscope in stable equilibrium with its spin axis parallel to the equator and irrespective of orientation of the device in any direction, said driving meansl being responsive to precessional movements of the gyroscope.

'7. In a gyroscopic device for indicating geographic positions, a gyroscope adapted to be set into operation with its axis parallel to the equator, a support adapted to be carried by a ship or like moving object, means interconnecting said support with the gyroscope and serving to carry the gyroscope for three degrees of freedom, said last means including a gimbal ring capable of having three degrees of freedom with respect 'to the support, and with respect to which the gyroscope is also capable of having like movement, said earths direction of rotation to maintain its angimbal ring being adapted to have gimbal axis of the same maintained parallel to the earths north and south axis and being likewise restrained against rotation about said axis, driving means interposed between said gimbal ring and the gyroscope and serving yto insure relative rotation between said ring and said 'gyroscope at a'rate equal to the rate oi.' rotation but in an opposite direction, and means serving. to modify said driving rate in accordance with. orientation of the ship in easterly or westerly directions, said last means including a -follow-up mechanism operative responsive to precessional movements of the gyroscope, and motive means actuated in response to the positioning of said follow-up mechanism.

8. In a gyroscopic device for indicating geographic positions in terms of longitude, a gyro scope adapted tov be set into operation with its spin axis parallel tothe plane of the equator, means. for eii'ecting retrograde rotation of lsaid gyroscope about an axis parallel to the polar axis of the earth and in a direction opposite to the gular position iixed with respect to absolute space, a repeater card having a plurality of graduated dials, means interconnecting said dials for automatically moving one of them relative to the other in accordance with the rotation oi' the earth about its axis, a housing for said dials, and means controlled by retrograde rotation of the gyroscope for moving said dials and interconnecting means relative to said housing in accordance with the rate of said retrograde rotation.

9. In a gyroscopic apparatus for indicating geographic positions in terms of longitude, a gyroscope, said gyroscope when in operation having its spinning axis disposed parallel to the plane of the equator, means for supporting the gyroscope for three degrees of freedom, motive means serving to apply forces to the gyrcscope to substantially neutralize tendency toward precessional movementsv as the apparatus is moved in various directions over the earths surface, and-means 20 responsive to slight precessional movements of the gyroscope for controlling said motive means.

FLETCHER M. YOUNG. 

